head light burns out Engine dos'nt run right

[BigD_83]

I'm getting 18.5 volts across battery.

Oh, crap...I'm surprised you're not getting smoke coming out of the battery with that kind of voltage. Keep an eye on it, as you have, or are probably very close, to having it run dry, which will likely cause a dead short in the plates.

I agree with posplayr and Brendan. A new R/R should be your first order of priority.

Where abouts in this big bad world are you located?

[Bud]

at rest 12.8V before starting idle 14.5 to 15V after checking battery at rest is 13.5V and droping

[Bud]

Millington IL USA

[Brendan W]

at rest 12.8V before starting idle 14.5 to 15V after checking battery at rest is 13.5V and droping

The 12.8 and 13.5V are slightly on the high side of normal. The idle voltage is high. With luck you just might have escaped battery damage. Make sure the electrolyte is topped up and keep an eye on it. If it's getting warm charging or you are losing electrolyte be aware that ( drama queen hat on) half filled batteries with shorting plates can go bang.